Field of the Invention
The present invention relates to an injection molding machine. Specifically, the present invention relates to an injection molding machine suitable for injection molding in which a molding material is a light metal.
Description of Related Art
An injection molding machine injects a predetermined amount of a molten material metered in an injection device into a cavity of a mold. In an injection molding machine that includes a melting device in which a molding material melts to generate a molten material and an injection device including an injection shaft which injects the molten material supplied from the melting device, a connecting member connecting the melting device and the injection device is provided. The molten material generated in the melting device is sent to the injection device through a communication path in the connecting member.
Since a predetermined pressure is applied to the molten material by the injection shaft during injection, it is necessary to close the communication path during injection in order to prevent the molten material from flowing back to the melting device through the communication path.
Here, an injection molding machine including a backflow prevention device configured to prevent a backflow of a molten material by bringing a valve rod into contact with a sealing seat formed in the communication path is known. Specifically, in Patent Literature 1, when a front of a valve rod is cooled, a semi-solid material in which the molten material is solidified halfway is generated, and the backflow is prevented.